In general, in case of digital broadcastings, control data for permission/prohibition of copying the broadcast programs are often transmitted as a program related data together with the video and audio data streams and the like which composing the programs. The transmitted copy regulation data are used for determining permission/prohibition of recording the program at the time of the program recording by a recorder such as D-VHS VCRs.
As an example of the copy regulation data, FIG. 14 shows a syntax structure of the digital copy regulation descriptor described in “ARIB STD-B10, Issue No. 1.2”, which defines the program sequence data used for the digital broadcasts such as the BS or CS broadcast in Japan. In the syntax structure there is a 2-bit field so-called “digital_recording_control_data”, which describes a copy generation control data. As shown in FIG. 15, these 2-bit fields data. “00”, “01”, “10” and “11” represent “unconditionally copy permitted”, “provider-conditioning copy”, “single copy permitted” and “copy protected”, respectively.
Also, in case of the limited reception programs, a program control data is included in the ECM (Entitlement Control Message) to be transmitted. And then a record control data for permission/prohibition of recording the program may be included in the ECM. According to “ARIB-STD-B25, Issue No 1.0” which defines a limited reception system for BS digital broadcasts in Japan, as a response of the subscription checking command, which is one of the command/response between an IC card according to ECM and IRD, there is a video record control field (8-bit). 3-bit fields including therein one bit of the video record control field, as shown in FIG. 16, represents “video recording prohibited”, “video recording permitted for subscribers only”, and “video recording permitted”. Based on these data, a permission/prohibition of recording the program in interest is determined by the receiver and then the process is executed.
By the way, in these days there is a time shift TV replay as an item of the promising functions in case that an accumulating media is provided on a receiver, which is randomly accessible to the media such as hard disc. The time shift TV replay is, as shown in FIG. 17, a function that enables TV replay while replaying a program from its beginning at an arbitrary time while the program on air is recorded. In this example, when a TV viewer has reserved a recording of program A from 8:00 PM, he can start the TV replay at any time, for example, from 8:30 PM, without waiting until the end of the program at 9:30 PM.
This time shift TV replay can be accomplished, if a temporal recording is possible without relying upon a long-lasting recording of the program. Also, this can be accomplished as this is different from a normal recording of the program, even if the replay is limited to a certain extent, for example, there is a limitation for such as a period allowed for replays or the maximum number of replays.
In the meantime, as described above, according to the subscription checking data on the copy regulation data and ECM, if the recording is permitted, the replay is also possible without limitation. While in case of “copy-protected” a TV replay is permitted only in a real time manner. For this reason, in the case of a function that has assumed a temporal recording/temporal replay, such as the time shift TV replay, it is accomplished only in case that the program is permitted for recording. Thus not only intentions of the contents-provider cannot be fully reflected, but also the interest of the TV viewers will be limited.
As described above, in case that feasible features in a temporal recording/temporal replay such as a time shift TV replay will be provided in receivers, such features had accomplished only for programs permitted their recording and capable of replay without limitation in the conventional system. Thus there were problems such as that the intention of the contents-provider cannot be reflected fully, so that the interest of the TV-viewer had been limited.
As described above, as to the program for the digital broadcasts, in case of the conventional copy regulation method, which controls recordings of video/audio data, there was no copy regulations for the temporal recording for the sake of the time shift TV replay. Therefore, there were problems that appropriate copy regulations acceptable to both of the contents-provider and the TV-viewer were not executed.